Drilling hook



1944- G. F. NICOLSON ET AL 2,338,349

DRILLING HOOK Original Filed Jan. 9, 1942 3 Sheets-Sheet l I /1'45. 2. 6mm 1? NM OLSON o I P/c/M/m A. HR 1:51., [NV/5N TORS 1 44- G. F. NICOLSON Em ,338, 9

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Jan. 4, 1 44- G. F. McoLoN ET AL 2,338,349

DRILLING HOOK Original Filed Jan. 9, 1942 5 Sheets-Sheet 5 GARTH E /V/COL.50/V,

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Patented Jan. 4, 1944 DRILLING HOOK Garth F. Nicolson, Huntington Park, and Richard K. Hertel, Los Angeles, Calif., assignors to Byron Jackson (30., Vernon, Califl, a corporation of Delaware Original application January 9, 1942, Serial No. 426,196. Divided and this application February 20, 1943, Serial No. 476,526

Claims.

This invention relates generally to drilling hooks and particularly to spring hooks such as are used in rotary well drilling operations.

A general object of the invention is to provide a hook of exceptionally rugged and durable construction and embodying improved features designed to better withstand the severe service to which rotary and casing hooks are subjected.

Another object is to provide a spring drilling and casing hook embodying a novel and improved swivel bearing arrangement which assures free swiveling action of the hook, especially under light loads.

Other objects and advantages will be apparent from the following detailed description of one embodiment of the invention, reference being had to the accompanying drawings wherein:

Fig. 1 is an elevation of a complete hook assembly embodying the invention;

Fig. 2 is a view, partly in elevation and partly in section, taken at right angles to Fig. 1;

Fig. 3 is an enlarged fragmentary longitudinal sectional view of the central portion of the hook, showing the swivel lock sleeve rotated through 180 from the position shown in Fig. 2;

Fig. 4 is a transverse section taken on line IV-IV of Fig. 3;

Fig. 5 is a transverse section taken on line VV of Fig. 3;

Fig. 6 is an elevation of the portion of the hook shown in Fig. 3, as viewed from the right-hand side of the latter figure, with parts broken away on line VIVI of Fig. 3;

Fig. '7 is a transverse section taken on line VII-VII of Fig. 6

Figs. 8 and 9 are views showing the swivel locking member in two different positions from that illustrated in Fig. 3;

Fig. 10 is a fragmentary elevational view of the swivel lock housing, as viewed from the right of Fig. 6;

Figs. 11 and 12 are enlarged fragmentary sectional views of the upper portion of the hook, illustrating the swivel bearing in two positions; and

Fig. 13 is a longitudinal section taken on line XIIIXIII of Fig. 1.

Referring to the drawings, and particularly to Figs. 1 and 2, the invention has been shown as incorporated in a hook comprising generally a hook body I pivotally connected to the lower extremity of a shank 2 by a pivot pin 3, the shank 2 being yieldably supported in a housing 4. A yoke or bail 5 is connected to the upper end of the housing for connecting the hook to the usual tice, the shank 2 is yieldably supported in the housing by a coil compression spring 6 interposed between a nut I threaded to the upper end of the shank and an inwardly projecting shoulder 8 at the lower end of the housing. Downward movement of the shank and hook, as the spring is compressed under load, is limited by a stop shoulder 9 formed in the housing 4.

It will be observed that the nut l is threadedly connected to the shank 2 by a relatively coarse left-hand thread I2, preferably of the modified Acme type, although it will be appreciated that any other type of thread may be used. The hook is most frequently rotated in clockwise direction, as viewed from above, as when making up to joints between sections of drill pipe or casing, and hence the provision of a left-hand thread tends to cause the nut to tighten instead of loosen during rotation. The thread is of the straight type, rather than tapered, and the nut is made up against a shoulder I3 on the shank 2. The nut 1 is securely locked in engagement with the shoulder I3 by a lock nut I4 which is threadedly connected to a reduced extension I5 on the shank, by a relatively fine left-hand thread It of less pitch than the thread I2. The lock nut is made up tightly against a flat shoulder on the upper surface of the nut I, and, due to the difference in pitch of the two threads, a powerful wedging effect is obtained. However, as a further safeguard against inadvertent loosening of the lock nut, a set screw I1 is preferably threaded in the lock nut and engages the shank extension I5 above the threads I6.

A sturdy and compact swivel locking arrangement has been provided, for releasably locking the hook body I and the shank 2 against rotation with respect to the housing 4, without interfering with the axial reciprocation of the shank in the housing. Referring to Figs. 3 to 10 inclusive, it will be observed that the lower portion I8 of the shank 2 is enlarged and formed of square cross-section, as shown most clearly in Figs. 4 and 5. The square portion I3 is slightly longer than the maximum axial travel of the shank, and affords a splined connection between the shank and a lock sleeve I9. As seen most clearly in Fig. 5, the lower portion of the sleeve I9, below the stop shoulder B -on the housing 4, is provided with a square opening it closely fitting the square portion of the shank. The sleeve extends upwardly around the lower cylindrical portion of the housing 4, and is rotatably supported thereon by a split clamp ring 2I (Figs. 3, 6 and 7).

As shown in Fig. 3, the outer wall of the housing 4 is recessed inwardly at 22, providing an up wardly facing shoulder 23 for supporting the clamp ring 25 against downward movement. The clamp ring comprises a pair of semi-circular segments i2 1 and 25, secured together about the housing i by bolts 26 and 2?. The lower portion of the clamp ring is cut away to provide an undercut recess 28, and the upper extremity of the lock sleeve I9 is provided with a similarly shaped annular rib 29 housed within the recess 28 and providing a rotatable interlocking connection between the lock sleeve and the clamp ring. The lock sleeve is thus mounted on the housing 4 for rotation with the shank 2 and hook body I, but is constrained against axial movement with respect to the housing.

In order to releasably lock the shank 2 against rotation with respect to the housing 4, a releasable locking connection is provided between the housing and the lock sleeve la. As shown most cleany in Fig. i, a plurality of circumferentially spaced slots 32 are formed in the lower portion of the housing l, and a locking member 33 is pivotally mounted on and enclosed within 2. laterally projecting housing 36 formed integral with the lock sleeve til, the member 33 being movable radially into or out of engagement with a selected one of the slots 32. The locking member is suitably keyed to a rock shaft 325 journaled in the housing and for this purpose the central portion of the rock shaft is provided with a pair of oppositely extending ribs or keys 33 and 3i which engage similarly shaped keyways (i8 and 39 in re hub of the locking member. To enable the rock shaft to be manually oscillated about its axis, and thus move the locking member into or out of engagement with one of the slots 32, one end of the rock shaft projects through the wall of the housing 34 and is provided with an enlarged head it on which are formed a pair of hook-shaped projections 4i and 42, as shown in Fig. 10. When the locking member 33 is in the locking position shown in Fig. 3, the head 4i) assumes the position indicated in solid lines in 10. If it is desired to move the locking member to its released position (Fig. 8), a downward pull is exerted on the projection H by means of the usual sheph'erds hook provided for that purpose, to rock theshaft in counter-clockwise direction, as viewed in Fig. 10, the head 46 then assuming the dotted line position indicated in the latter figure. Similarly, a downward pull on the projection 42 causes the locking member to move from released to locked position.

A spring toggle mechanism is associated with the locking member 33 for yieldably maintaining the locking mechanism in either locking or released position. As shown most clearly in Figs. 3, 6, 8 and 9, a double-faced cam -55 is formed integral with and projects outwardly from the hub of the locking member, and is provided with oppositely directed cam faces 45 and ill. One cam face or the other is adapted to be selectively engaged by a roller 18 mounted on the free end of a rockerarm 49 journaled on a pin or bolt iii! mounted in the housing 3 and extending parallel to the rock shaft 35. The rocker arm is yieldingly urged in a counter-clockwise direction, as viewed in Figs. 3, 8 and 9, by a torsion spring til having one end thereof engaging an abutment 52 on the housing 34 and. the other "end engaging an abutment 53 on the rocker arm.

in Fig. 3, the roller 43 enil and urges it in counterclockwise direction, thus yieldingly maintaining the locking member this position. As the rock shaft 35 is rotated to move the locking member to its released position, the cam face il' forces the rocker arm downwardly against the action of the spring until the roller passes the apex of the cam and engages the other cam face Mi. Thereupon the rocker arm urges the locking member in clockwise direction, moving it into the released position indicated in Fig. 8.

It will be observed, with particular reference to Figs. 3 and 9, that the locking member is provided with two angularly faces 55 and 5% on the side thereof facing the housing #3. The upper face 55 is so disposed when the locking member engages one of the slots iii, the face 55 extends parallel to the axis of the shank and flush with the inner wall of the housing. a pair of laterally extending wings 5i and 58 (Fig. 6) being provided on the locking member to limit its inward movement. The lower face 56 is angularly disposed with respect to the upper face 55, so that if the locking member should be rocked inwardly but should not align with one of the slots 59, the face 56 will extend parallel to the outer wall of the housing t when it engages the latter, as indicated in Fig. 9. It will be observed that in this position of the locking member, the roller 63 engages the inner cam face 4'! and urges the locking member toward locking position. It will therefore be evident that if the hook body i and shank 2 are then rotated slightly, to align the next adjacent slot 32 with the locking member, the latter will automatically snap into the slot under the action of the spring 5i. This arrangement dispenses with the necessity of maintaining a downward manual pull on the projection while the hook is being rotated to align a slot 32 with the locking mem ber.

It will be understood by those familiar with ing position shown gages the cam face rotary and casing hooks that the spring 3 is Gil full load when this is desired.

only of sufiicient strength to support a single stand of drill pipe, and that when the entire drill string is suspended from the hook the spring compresses and allows the hook body and shank to descend until the stop shoulder '9 is engaged, thus transferring the load directiy from the shank nut l to the stop shoulder. It ha been customary to interpose an anti-friction-bearing between the shank nut and the stop shoulder, to provide free swiveling of the hook bod under In prior constructions, the same bearing has also been 50 arranged as to be interposed between the upper extremity of the spring and the lower face of the shank nut, in order to provide free swiveling .of'the shank and nut with respect to the spring; Freedom of rotation of the hook body, shank and shank nut is especially desirable when the hook :is under light load, inasmuch as it is customary to rotate the hook manually in order to turn the elevator suspended therefrom into .a predetermined oriented position while it is near the derrick 'floor, each time a stand of pipe is added to the drill string during the operation of running the drill string into the well. The provision of a single bearing interposed between the shank nut and both the spring and the stop shoulder is, however, objectionable for the following reason:

During the drilling operation, the Weight of the drill string is transferred from the hook shank to the housing through the shank nut and the bearing. The hook is locked against rotation during drilling, and hence for long periods of time each of the bearing balls or rollers occupies a fixed position with respect to the bearing races, and the vibration and the gyratory motion transmitted to the hook from the drill string during drilling often causes the bearing members to wear grooves or indentations in the bearing races. It is obvious that the presence of a series of indentations in the bearing races interferes with the freedom of rolling action when it is desired to rotate the hook, and this i particularly noticeable when the hook is rotated manually to orient the elevator.

In order to overcome the aforementioned difficulty, we have provided a bearing construction incorporating a main bearing BE! (Figs. 11 and 12) interposed between the shank nut I and the stop shoulder 9, and an auxiliary bearing 6! interposed between the shank nut and the upper end of the spring 6. Since th spring i always maintained under an initial precompression, the auxiliary bearing is retained thereby in engagement with the nut T and moves verticall with the nut during compression and expansion of the spring. It is also deemed preferable to mount the main bearing in such a manner that it also moves vertically with the nut. To accomplish this, a dual bearing retainer 62 i provided, and it will be observed that this retainer not only maintain the races and balls of each bearing in assembled relation, but also serves to support the main bearing 65! from the auxiliary bearing 6!.

The retainer comprises a one-piece structure which may be pressed to shape from sheet stock, with the upper and lower extremities initially straight to permit the auxiliary bearing iii to be inserted from the upper end and the main bearing 6!] to be applied from the lower end. After the bearings are assembled on the retainer, th upper edge is rolled inwardly to form a lip 63, and the lower ed e is rolled outwardly to form a lip 64, to securely retain the hearings in place.

Attention is directed to the fact that the retainer is supported by the upper race 65 of the bearing El, and that a clearance is provided between the lower race 66 of that bearing and an upwardly facing inclined shoulder '61 on the retainer. In a similar manner, the spacing of the lower outwardly bent lip 64 and the downwardly facing shoulder 63 on the retainer is such as to provide clearance between one of these shoulders and the respective race 69 or ill of the bearing Bil. These clearances are exaggerated in Figs. 11 and 12 of the drawings, for illustrative purposes, and in actual practice may be only a few thousandths of an inch.

When the spring 6 is expanded and the main bearing Bil is out of contact with the stop shoulder, as indicated in Fig. 11, the bearing is supported solely by the lower lip 64 of the retainer. During rotation of the hook body, shank and shank nut under these circumstances, the main bearing to obviously will rotate as a unit with the retainer 62, the nut I, and the upper race 65 of the auxiliary bearing 61, relative rotation taking place between the races 65 and 85 of the auxiliary bearing. The latter bearing is never loaded in excess of the compression strength of the spring 6, and hence it is not subject to the grooving action which occurs in the main bearing during drilling. It will, therefore, remain in good operating condition for a long period of time, provided it is properly lubricated.

In Figs. 11 and 12., a lubricant fitting I2 is provided in the nut I, to which access is had upon removal of a suitable closure plug (not shown) in the housing 4. A series of openings I3 are provided in the retainer 52 in the horizontal plane of the fitting '12, for admitting lubricant to the bearing ti. Lubricant from this fitting will also work downwardly into the main bearing (iii, and, as shown in Fig. 1, the main bearing may also be separately lubricated through a fitting 74 in the housing. In addition to or in lieu of the fitting l2, a lubricant fitting 75 (Fig. 2) may be provided in the nut l, to which access is obtained by removal of the cover plate it which closes the upper end of the housing 4.

Referring to Fig. 12, wherein the parts are shown in the position they assume when the hook is heavily loaded, it will be observed that the main bearing is now supported on the stop shoulder 9, and that clearance is provided between the lower lip 64 of the retainer and the lower race 69 of the bearing. The upper race it engages the shoulder 68 on the retainer, but this is not objectionable inasmuch as these members rotate as a unit with the nut I and the upper race 65 of the auxiliary hearing. The main bearing provides free swiveling between the shank nut and the stop shoulder 9, while the auxiliary bearing enables the nut to rotate with respect to the spring 6.

Referring now to Figs. 1 and 13, it will be observed that the hook body I includes a bill 89 providing a recess Si for receiving a load-sustaining member such as a swivel bail, indicated in dotted line at 52. The recess is adapted to be closed by a locking arm 83 pivoted to the bill at 8 3, and suitable latching mechanism, indicated generally at 35, is provided for releasably latching the arm in closed position. It is preferable that the locking arm be automatically closed as the swivel ball or other load-carrying member is inserted into the recess 3i, and for this purpose a closing finger 3b is formed integral with the look-- ing arm and projects inwardly therefrom so as to be engaged by the bail 82 as the latter enters the recess 83. As shown most clearly in Fig. 13, the closing finger is of inverted U-shape in crosssection, and extends downwardly along each side of the bill 85 of the hook a sufficient distance to embrace the bill when the locking arm is in open position, thus avoiding the possibility of a member of the drilling crew having his fingers caught between the closing finger and the upper surface of the bill.

The upper surface 8! of the closin finger is convex in the plane of Fig. 13, and preferably conforms to the curvature of the under side of a standard swivel bail of the same capacity as the hook. The lower surface of the closing finger and the upper surface 88 of the bill are also convex in the plane of Fig. 13, and are preferably concentric with the upper surface 81. In the plane of Fig. 1, the surface 81 is concave, preferably conforming to the cross-sectional contour of the swivel bail 532, and the lower surface of the closing finger and the upper surface 88 of the bill are also preferably concave, and concentric with the surface 87. In this manner, the maximum bearing area is provided between the swivel bail and the closing finger, and between the latter and the bill 80.

From the foregoing description of a preferred embodiment of the invention, it will be apparent that a drilling hook has been provided which is of very rugged and durable construction, and in which the features which, in the past, have proved to be most troublesome, have been so designed as to eliminate the most frequent sources of trouble.

It is to be understood, of course, that the specific details of construction shown and described are subject to modification in various respects, and that the invention is not limited to such details but is of the full scope of the appended claims.

This application is a division Of our co -pending application Serial No. 426,196, filed January 9, 1942, for Drilling hook.

We claim:

1. In a device of the class described, the combination of a body having a central bore and a pair of axially spaced internal shoulders, a shank mounted in the bore for rotary and longitudinal movement relative to the body and having an enlarged head at one end thereof, resilient means interposed between the head and one of said shoulders, bearing means interposed between the head and the resilient means, other bearing means interposed between the other shoulder and the head, and means supporting said last-named bearing means for longitudinal movement with said shank and relative to the body.

2. In a device of the class described, the combination of a body having a central bore and a pair of internal shoulders, a shank mounted in the bore for rotary and longitudinal movement relative to the body and having an enlarged head at one end thereof, resilient means interposed between said head and one of said shoulders, bearing means interposed between said resilient means and said head, other bearin means interposed between the other shoulder and the head, and means carried by the first bearing means for supporting the second bearing means and maintaining the latter adjacent to said head during longitudinal movement of said shank relative to the body.

3. In a hook structure, the combination of a body having a central bore and a pair of axially spaced shoulders, a stem mounted in the bore for rotary and longitudinal movement relative to the body, said stem having an enlarged head at one end, resilient means interposed between the head and one of said shoulders, bearing means interposed between the resilient means and the head, retainer means associated with said bearing means for maintaining the parts thereof in assembled relation, and other bearing means interposed between the other of said shoulders and said head and supported by said retainer means.

4. In a hook structure, the combination of a body having a central bore, a stem slidable and rotatable in the bore and having a head adjacent one end thereof, spring means interposed between the head and the body, a shoulder on the body for limiting axial movement of the stem in one direction relative to the body, main bearing means interposed between the shoulder and the head and being effective to transmit axial thrust between the stem and the body only when the stem is in one extreme position relative to the body, other bearing means interposed between the head and the adjacent end of the spring means and being effective to transmit a spring-supported load between the stem and the spring means in all axial positions of the stem, and means supporting said first bearing means for movement with the stem axially of the body,

5. In a drilling hook, a duplex bearing assembly comprising a relatively small diameter, lightduty antiiriction bearing adapted to sustain only a spring load and including upper and lower races and bearing elements therebetween, a relatively large diameter, heavy-duty antiiriction bearing adapted to sustain the full load on the hook in excess of the spring load and including upper and lower races and bearing elements there-between, and common retaining means for retaining the races and bearing elements of each of said bear ings in assembled relation and retaining the bear ings in fixed axial relation to each other, said means comprising a retainer ring having a portion surrounding the light-duty bearing and a portion surrounded by the heavy-duty bearing, said ring having a pair of opposed, inwardly projecting shoulders between which the light-duty bearing is confined, and a pair of opposed, outwardly projecting shoulders between which the heavy-dut bearing is confined,

GARTH F. NICOLSON. RICHARD K. HERTEL. 

